dismounted a scope today, I noticed the scope tube is slightly creased where the rings where. the front ring pushed in the scope tube more than the rear ring. The scope is indented pretty much the whole way around the tube, I have never had this happen before its not like the rings where misaligned but rather the ring diameter too small or the scope tube slightly oversized It did not scratch the tube, just left 2 indents the exact size of the rings. this is the 3rd scope I have had on this rifle and never had a problem before, the scope is a sightron SI and the rings are ruger. perhaps I just overtightend the rings??? BTW when I went to take the scope off the screws didnt' seem that tight

I'm going to presume that the "dents" are mostly on the bottom side and are very narrow, rather than being the width of the ring.

I have noticed that some Ruger factory rings appear to sit and something other than a 90 degree angle to the receiver; in other words, they tilt forward or rearward slightly. This tilt causes one edge of the ring to bite into the scope when the ring cap is tightened.

IF this is the case with your gun, to prevent it in the future you could place the rings on the gun but not fully tighten the base clamp. Then place the scope in the rings and tigthen the caps. After the scope is secured in the rings, fully tighten the base clamps. This procedure should place the misalignment at the base where the steel-to-steel mating will not be harmed, rather than at the scope where the aluminum tube can be bent.

Of course if this is not your problem, then happily disregard these comments

Another possibility occured to me: If you have not experience this denting problem with other scopes in the same mounts on the same gun, then it could be due to either softer or thinner aluminum in the scope tube you've had troble with.

Just as with steel, the hardness of aluminum alloys vary, as does gage of metal that manufacturers use. I'm not implying anything about the particular scope you've had a problem with, but it is worth investigating.

Cummins cowboy: I have been lapping ALL my scope rings for the last 15 years now and this simple, obscure and easy to do procedure has virtually put an end to a long list of "problems" that used to plague me and my scopes AND Rifles!
Let alone the esthetics of the scopes and then theres the increase in resale value of the scopes when proper lapping and alignment of the rings has been done for them.
Did you lap the rings before mounting the scope?
Anyway I have two excellent scope ring lapping systems (tools!) to recommend for you. The first is made by Russ Haydon of Russ Haydons Shooters Supply and the other set I take turns using is the slightly more "agrressive" tool offered by Koko Pelli (made in Montana!).
Take your dial calipers to both the rings and the scope tube - see whats what there.
By the way I also take extreme care to VERIFY that the front face of the front ring is absolutely "perpindicular" (thus the 1" hole shall thus be "aligned" with the rifles bore) to the line of the bore when setting up my mounting jobs and I do this of course prior to lapping.
Then I align the two rings with the lapping rod making sure NO gaps at all will be around the scopes tubes. Next I then "bore sight" my ring to ring alignment by simply laying the scope in the ring bottoms and making sure the scope is now reasonably aligned with the bore (bore sighted) before any top ring tightening is done.
Frankly I am puzzled by your "damage" and can not remember having a similar situation crop up.
Usually the "ring marks" do not completely circumnavigate the entire tube or are of the extent as to damage your scope tube (other than mar it).
I pray you did not use the scope tube to "twist (torque) in the front ring!
Thats another whole kettle of problem fish there!
I wish I could be more help but you have a weird one there, I think, cummins cowboy!
I hope the scope is not damaged to the point of not performing properly!
Hold into the wind
VarmintGuy